Combustor assembly

ABSTRACT

A combustor assembly for a gas turbine engine comprises a casing arrangement defining an aperture and a seal element mounted on the casing arrangement through which a component of the combustor can extend. The seal element comprises a relatively flexible force absorbing portion and a relatively rigid sealing portion. The force absorbing portion is provided between the sealing portion and the casing arrangement. The force absorbing portion is resiliently deformable to absorb force during movement of the casing arrangement. Such resilient deformation restricts transmission of the forces to the sealing portion. The seal element may be configured to carry a seal member.

This invention relates to combustor assemblies for gas turbine engines.

The fuel injectors for the combustor of a gas turbine engine extendthrough apertures in the combustion outer casing and the combustionsupport casing of the engine. The injector is bolted to the combustorsupport casing, but is movable relative to the combustor outer casing,which occurs due to movement of the casings during operation of theengine.

The injector is mounted on a seal carrier carrying a sealing ring, whichsealingly engages against the inner wall of a cylindrical seal liner.However, this arrangement has the disadvantage that, as the combustorouter casing becomes distorted due to thermal and mechanical loadsplaced on it during engine running, the shape of the aperture throughwhich the injector extends also becomes distorted to an oval shape. Thismeans that the sealed carrier no longer sealingly engages against theinner surface of the liner, and leakage occurs.

According to one aspect of this invention, there is provided a combustorassembly for a gas turbine engine, the combustor assembly comprising: acasing arrangement defining an aperture; and a seal element mounted onthe casing arrangement at said aperture through which a component of thecombustor can extend; characterised in that the seal element comprises arelatively flexible force absorbing portion and a relatively rigidsealing portion, the force absorbing portion being provided between thesealing portion and the casing arrangement, and the force absorbingportion being resiliently deformable to absorb forces during movement ofthe casing arrangement, whereby such resilient deformation restrictstransmission of the forces to the sealing portion.

The sealing portion may comprise a holder and may further include theseal member, which may be held by the holder.

The seal element may be annular in configuration. The force absorbingportion may be annular in configuration. The sealing portion may beannular in configuration. The force absorbing portion and the sealingportion may be concentric with respect to one another. The forceabsorbing portion may extend around the sealing portion.

The force absorbing portion may comprise a curved member, which may besemi-circular or of varying radius.

The holder may define an inwardly facing recess, such that the sealmember extends inwardly from the holder.

The combustor assembly may further include a seal engagement memberagainst which the seal member can seal. The aforesaid component of thecombustor may be mounted on the engagement member. The engagement membermay define a tubular portion through which the component can extend. Theengagement member may comprise a securing portion to seal the aforesaidcomponent to the engagement member. The securing portion may comprise aflange, which may be cooperable with fastening means to fasten theengagement member to the component.

The casing arrangement may comprise an outer casing. The casingarrangement may further include an inner casing. The engagement membermay be secured to the inner casing, preferably via the securing portion.

In the preferred embodiment, the aforesaid component of the combustorcomprises a fuel injector.

Preferably, the combustor is of an annular configuration comprising aplurality of the aforesaid component spaced from each other. The casingarrangement may define a plurality of the apertures spaced from oneanother. The seal element may be generally circular in configuration,and the force absorbing portion may comprise a diaphragm. Preferably,the force absorbing portion comprises a curved region to provide atleast some of the flexibility.

The seal element may comprise a mounting portion extending from theforce absorbing portion to secure the seal element to the casingarrangement. The mounting portion may comprise a flange extending aroundthe seal element.

The engagement member may be substantially cylindrical in configurationand at least part of the aforesaid component of the combustor may extendgenerally along the main axis of the cylinder.

Preferably, the seal member is generally circular in configuration. Theseal member may have an inwardly facing sealing surface, to seal againstan outwardly facing sealing surface of the engagement member.

An embodiment of the invention will now be described by way of exampleonly, with reference to the accompanying drawings, in which:

FIG. 1 is a sectional side view of the upper half of a gas turbineengine;

FIG. 2 is a diagrammatic view of a region of a combustion assembly;

FIG. 3 is as diagrammatic view of a region marked III in FIG. 2;

FIG. 4 is a top plan view of a seal carrier; and

FIGS. 5A and 5B are alternative configurations of a force absorbingportion.

Referring to FIG. 1, a gas turbine engine is generally indicated at 10and comprises, in axial flow series, an air intake 11, a propulsive fan12, an intermediate pressure compressor 13, a high pressure compressor14, a combustor assembly 15, a high pressure turbine 16, an intermediatepressure turbine 17, a low pressure turbine 18 and an exhaust nozzle 19.

The gas turbine engine 10 works in a conventional manner so that airentering the intake 11 is accelerated by the fan 12 which produce twoair flows: a first air flow into the intermediate pressure compressor 13and a second air flow which provides propulsive thrust. The intermediatepressure compressor compresses the air flow directed into it beforedelivering that air to the high pressure compressor 14 where furthercompression takes place.

The compressed air exhausted from the high pressure compressor 14 isdirected into the combustor assembly 15 where it is mixed with fuel andthe mixture combusted. The resultant hot combustion products then expandthrough, and thereby drive, the high, intermediate and low pressureturbines 16, 17 and 18 before being exhausted through the nozzle 19 toprovide additional propulsive thrust. The high, intermediate and lowpressure turbine 16, 17 and 18 respectively drive the high andintermediate pressure compressors 14 and 13, and the fan 12 by suitableinterconnecting shafts.

Referring to FIG. 2, there is shown a region of the combustor assembly15 comprising an annular combustor 20 defining a plurality of upstreamapertures 22, each receiving a nozzle 24 of a fuel injector 26.

An annular casing arrangement 28 extends around the combustor 20 andcomprises an inner casing 30, and an outer casing 32. The inner casing30 defines a plurality of apertures 34 through each of which arespective one of the fuel injectors 26 can extend. Similarly, the outercasing 32 defines a plurality of outer apertures 36 through each ofwhich the fuel injector 26 can extend.

In order to seal the fuel injector 26 relative to the outer casing 32, aseal assembly 38 is provided at each of the apertures 36 in the outercasing 32. The seal assembly 38 comprises a seal element in the form ofa radially outer seal carrier 40 having a relatively flexible annularforce absorbing portion 42, and a relatively rigid sealing portion 44.

Referring to FIG. 3, there is shown a sectional side view of the sealassembly 38 which it can be seen that the sealing portion 44 comprises acircular holder 46 defining an annular recess 48 in which an annularseal member 50 is held. The holder 44 comprises an annular upper portion52 integral with the force absorbing portion 42, and an annular lowerportion 54 attached to the upper portion 52 by rivets 56. A plurality ofthe rivets 56 are provided in spaced relationship around the sealingportion 44 to secure the upper and lower portions 52, 54 together,thereby holding the sealing member in the recess 48.

A seal engagement member in the form of a cylindrical tube 58 is mountedon a flange 60 of the fuel injector 26. The cylindrical tube 58 can beintegral with the fuel injector 26, or it can be secured thereto bysuitable securing means for example bolts 61A, extending through aflange 61B (shown in broken lines in FIG. 3) on the cylindrical tube 58.

The cylindrical member 58 has an outer surface 62 against which thesealing member 50 engages and seals to prevent leakage of air throughthe aperture 36. In view of the fact that the diameter of the tubularmember 58 is much less than the diameter of the aperture 36, the levelof sealing is considerably greater than with prior art sealingassemblies.

An annular securing flange 64 extends around the force absorbing portion42 and defines a plurality of apertures 66 to receive bolts 68. Thebolts are secured in threaded holes 70 in the outer casing 32.

The flexible force absorbing member 42 comprises a circular curvedportion 72 of the seal carrier 40. The circular curved portion 72 iscapable of resilient deformation during movement of the outer casing 32relative to the inner casing 30. As a result, the forces created by themovement of the outer casing relative to the inner casing 30 areabsorbed by the force absorbing portion 42, by virtue of its flexiblenature and are not transmitted to the sealing portion 44. Thus, thesealing portion 44 is not distorted and remains in a generally circularconfiguration thereby maintaining appropriate sealing against the outersurface 62 of the tubular member 58.

As can be seen from FIG. 4 which shows a top plan view of the sealassembly 38, the seal carrier 40 is of a circular configuration, wherebythe relatively flexible force absorbing portion 42 is also of a flexibleconfiguration and extends around the sealing portion 44. As can be seen,the sealing portion 44 is also of a flexible configuration.

There is thus described a preferred embodiment of a combustor assembly15 comprising a seal assembly 38, in which the seal carrier 40 has asealing portion 44 which is held against a cylindrical tubular portion58 by a flexible force absorbing portion 42. The force absorbing portionprovides an advantage in the preferred embodiment in that it can absorbthe distortion forces created by the movement of the outer casing 32relative to the inner casing 30, thereby maintaining the seal againstthe tubular member 58.

Various modifications can be made without departing from the scope ofthe invention, for example, the tubular member 58 can be releasablymounted on the fuel injector 26. Also, the force absorbing portion couldbe of different configurations, for example as shown in FIGS. 5A and 5B.In FIG. 5A, the force absorbing portion 42 comprises three alternatingcircular curved portions 74, 76, 78. The three curved portions 74, 76,78 alternate with each other, as shown, and comprise a first convexportion 74, being convex in a radially outward direction with respect tothe combustor, a concave portion 76, being concave in a radially outwarddirection and a second convex portion 78, being also concave in aradially outward direction. The three curved portions 74, 76, 78 areannular and concentric with respect to one another.

In FIG. 5B, the force absorbing portion comprises an annular convexportion 80, having the convex region facing inwardly of the seal carrier44, and annular concave portion 82, having the concave region facinginwardly of the seal carrier 44. The convex portion 80 and the concaveportion 82 are annular and concentric with respect to each other.

Whilst endeavouring in the foregoing specification to draw attention tothose features of the invention believed to be of particular importanceit should be understood that the Applicant claims protection in respectof any patentable feature or combination of features hereinbeforereferred to and/or shown in the drawings whether or not particularemphasis has been placed thereon.

1. A combustor assembly for a gas turbine engine, the combustor assemblycomprising: a casing arrangement extending around a combustor, thecasing arrangement defining an aperture; and a seal element mounted onthe casing arrangement at said aperture through which a component of thecombustor can extend, the component having a central axis, wherein theseal element includes a relatively flexible force absorbing portion anda relatively rigid sealing portion, the force absorbing portion beingprovided between the sealing portion and the casing arrangement, and theforce absorbing portion being resiliently deformable in a directionperpendicular to the central axis to absorb forces during movement ofthe casing arrangement, whereby such resilient deformation restrictstransmission of the forces to the sealing portion.
 2. A combustorassembly according to claim 1 wherein the sealing portion includes aholder and a seal member, the seal member being held by the holder, andthe sealing portion is configured to allow axial movement between thecasing arrangement and the combustor.
 3. A combustor assembly accordingto claim 1 wherein the seal element and the force absorbing portion areannular in configuration.
 4. A combustor assembly according to claim 1wherein the sealing portion is annular in configuration, and the forceabsorbing portion and the sealing portion are concentric with respect toone another, such that the force absorbing portion extends around thesealing portion.
 5. A combustor assembly according to claim 1 whereinthe force absorbing portion comprises a curved portion.
 6. A combustorassembly according to claim 5 wherein the curved portion is generallysemi-circular.
 7. A combustor assembly according to claim 5 wherein thecurved portion is of a varying radius.
 8. A combustor assembly accordingto claim 2 wherein the holder defines an inwardly facing recess, suchthat the seal member extends inwardly from the holder.
 9. A combustorassembly according to claim 8 wherein the combustor assembly furtherincludes a seal engagement member against which the seal member canseal, whereby the aforesaid component of the combustor can be mounted onthe seal engagement member.
 10. A combustor assembly according to claim9 wherein the seal engagement member defines a tubular portion throughwhich the component can extend.
 11. A combustor assembly according toclaim 9 wherein the seal engagement member comprises a securing means tosecure the aforesaid component to the engagement member.
 12. A combustorassembly according to claim 11 wherein the securing means comprises aflange, which is cooperable with fastening means to fasten the sealengagement member to the component.
 13. A combustor assembly accordingto claim 12 wherein the fastening means comprise bolts.
 14. A combustorassembly according to claim 9 wherein the seal engagement member isintegrally mounted on the aforesaid component of the combustor.
 15. Acombustor assembly according to claim 9 wherein the casing arrangementcomprises an outer casing and an inner casing, and the seal engagementmember is secured directly or indirectly to the inner casing.
 16. Acombustor assembly according to claim 15 wherein the seal engagementmember is secured to the inner casing via the securing means.
 17. Acombustor assembly according to claim 1, wherein the combustor is of anannular configuration, and a plurality of the aforesaid components arespaced from each other around the combustor.
 18. A combustor assemblyaccording to claim 17 wherein the casing arrangement defines a pluralityof the apertures spaced from one another, each aperture being configuredto receive a respective one of the aforesaid components.
 19. A combustorassembly according to claim 1 wherein the seal element is generallycircular in configuration, and the force absorbing portion comprises adiaphragm.
 20. A combustor assembly according to claim 19 wherein theforce absorbing portion comprises a curved region to provide at leastsome of the flexibility.
 21. A combustor assembly according to claim 1wherein the seal element comprises a mounting portion extending from theforce absorbing portion to secure the seal element to the casingarrangement.
 22. A combustor assembly according to claim 21 wherein themounting portion comprises a flange extending around the seal element.23. A combustor assembly according to claim 11 wherein the sealengagement member is substantially cylindrical in configuration and atleast part of the aforesaid component of the combustor extends generallyalong the main axis of the cylinder.
 24. A combustor assembly accordingto claim 23 wherein the seal member is generally circular inconfiguration, and has an inwardly facing sealing surface, to sealagainst an outwardly facing sealing surface of the seal engagementmember.
 25. A gas turbine engine incorporating a combustor assemblyaccording to claim 1.